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A modem is developed for information transmission in HF channel with transmission rate of 1200-4800 byte/s
A modem has perfomance data
Frequency range: 300-3400 Hz, in basic mode-500-3000 Hz (could be narrowed and extended by software) Operation concept: multifrequency (parallel) with PSK modulation and optimum noncoherent reception. One is used, two and three multiple phase modulation. The basic rates: 600, 1200, 2400, 3600 è 4800 bit/sec. The stable work is provided for frequency shift ±100 Hz. Error Correcting technique: Trelliss Code Modulation with interliving, Viterby algorithm. Time of synchronism: is no more than 0.5 s for frequency shift of ±10 Hz, is no more than 2.5 s for frequency shift of ±100 Hz. Interface: analog - based on TLC32046, digital - RS-232C.
Implementation: 1 TMS320C31 DSP (for C25 and C50 is under development):
Power consumption: not more than 5 W. Input line-symmetric, 600 Oh, with dynamic range -5 dB up -35 dB. Output line-symmetric, 600 Oh, with dynamic range +3 dB up -35 dB. Plate dimensions: 1,2 dm2. Modem's supply 5 V.
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